After oxygen, the thing your body needs most is water. This is no truer than when it comes to your fitness programme. If you’re dehydrated, not only will you get less than your best out of your workout; you could also put your wellbeing at serious risk. That said, drinking too much water can also hinder your wellness, so what’s an exerciser to do?
According to Becky Hand, RD, and Personal Trainer Dean Anderson, ‘Obviously, people differ a lot in body size, how much they sweat, the type and amount of exercise they do, and the climate in which they exercise. All these factors make one-size-fits-all recommendations on drinking water ineffective or even dangerous. An approach used by competitive marathoners in hot, humid weather isn’t going to make much sense for you if you’re jogging or walking for 30 minutes on a treadmill in an air-conditioned gym (or vice-versa). Therefore, a competitive athlete could benefit greatly from an assessment of individualised fluid, electrolyte and energy needs by a Registered Dietician with experience in sports nutrition.’ Although it sounds complicated, the good news is that staying hydrated during exercise really isn’t that difficult for most people.
Hand and Anderson note, ‘If your typical exercise session is around 60 minutes or less, and doesn’t involve vigorous activity outdoors in hot, humid weather, you probably don’t need to interrupt your exercise session for a drink unless you prefer to. A healthy, average-sized person can produce as much as 32oz of sweat during an hour of moderate to vigorous indoor exercise. That may feel and look like a lot of sweating, but it shouldn’t be enough to cause problems unless you’ve been seriously short-changing yourself on fluid intake prior to starting your exercise. You can tell whether that’s a potential problem by checking your urine colour before exercise. If it’s dark yellow with a strong urine smell, it’s a good idea to have a cup or two of water 30-60 minutes before you start exercising. If it’s clear to light yellow, it should be fine to just re-hydrate gradually after your exercise session without worrying about stopping to drink during the middle of it.’
The AmericanCollege of Sports Medicine states that your exercise performance is likely to be affected when the amount of sweat you product causes you to lose 2% or more of your normal (hydrated) body weight. ‘At this level of mild dehydration, you’ll probably be a little thirsty (though many people don’t experience thirst until they’re already dehydrated), and you may start to feel as if you have to work significantly harder to maintain your performance level,’ Hand and Anderson explain. ‘As dehydration gets progressively more severe, you may start to feel light-headed, uncoordinated, or have muscle cramps. If you continue, you may start experiencing the symptoms of heat exhaustion, and that can progress to heat stroke, which is potentially fatal and needs immediate medical attention.’
Hand and Anderson add, ‘The goals of fluid intake during exercise are to prevent dehydration from occurring and to not drink in excess of one’s sweating rate. One good way to figure out whether you need to drink something during your workout is to simply weigh yourself (without clothes) just before and after a typical workout. If your weight change is more than 2% of your starting weight, then in the future, you should plan to drink enough water during your workout to keep your post-workout weight within that 2% range. Typically, drinking a cup (8 oz) of water every 15-20 minutes will do the trick in all but the most extreme situations.’